Reland "[iOS] Updating enable/disable items in the Google Services settings"

This reverts commit 5f3d09d3.

Reason for revert: ios-simulator was flaky. I reverted the original patch aggressively because the issue was marked as "tree closers". Relanding it now.

Original change's description:
> Revert "[iOS] Updating enable/disable items in the Google Services settings"
> 
> This reverts commit 3b62417e.
> 
> Reason for revert: Suspecting this patch caused gclient runhooks failing on ios simulator. https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/ios-simulator-xcode-clang/58250
> 
> Original change's description:
> > [iOS] Updating enable/disable items in the Google Services settings
> > 
> > "Google activity controls", "Encryption", and "Manage synced data..."
> > is enabled when the user is authenticated and disabled otherwise.
> > 
> > Screenshot shared with Chromium accounts:
> >   + Signed out:
> > https://drive.google.com/open?id=19lXF2SdgpLdHUlTZ4WpxipDBdQNCshbU
> >   + Signed in with consent accepted:
> > https://drive.google.com/open?id=1SV3HhbG3hAbre5mSe06Dhjda4dJC4cck
> >   + Signed in with consent not accepted:
> > https://drive.google.com/open?id=1r5umMw6vf8yzh8X7V8V6LzRJVJLq8Rxs
> > 
> > Bug: 883101
> > Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
> > Change-Id: I3e2180c83f42adccb2717f2fdb96efa254751bbc
> > Reviewed-on: https://chromium-review.googlesource.com/c/1290937
> > Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
> > Reviewed-by: Sergio Collazos <sczs@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#601537}
> 
> TBR=jlebel@chromium.org,sczs@chromium.org
> 
> Change-Id: Iac738ad46478cda09124b37b22b8936a8f8d7e20
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 883101
> Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
> Reviewed-on: https://chromium-review.googlesource.com/c/1293758
> Reviewed-by: Yi Gu <yigu@chromium.org>
> Commit-Queue: Yi Gu <yigu@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#601580}

TBR=jlebel@chromium.org,sczs@chromium.org,yigu@chromium.org

Change-Id: I65dadf64329be701eb5df6e99a183de60f9ad3d3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 883101
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Reviewed-on: https://chromium-review.googlesource.com/c/1293996Reviewed-by: Yi Gu <yigu@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601611}

ios/chrome/browser/ui/settings/google_services_settings_mediator.mm

@@ -611,7 +611,9 @@ textItemWithItemType:(NSInteger)itemType
   BOOL enabled = self.isAuthenticated && !self.isConsentGiven;
   [self updateSectionWithCollapsibleItem:self.syncPersonalizationItem
                                    items:self.personalizedItems
-                                 enabled:enabled];
+                  collapsibleItemEnabled:enabled
+                       switchItemEnabled:enabled
+                         textItemEnabled:self.isAuthenticated];
   syncer::ModelType autofillModelType =
       _syncSetupService->GetModelType(SyncSetupService::kSyncAutofill);
   BOOL isAutofillOn = _syncSetupService->IsDataTypePreferred(autofillModelType);
@@ -627,16 +629,21 @@ textItemWithItemType:(NSInteger)itemType
   BOOL enabled = !self.isAuthenticated || !self.isConsentGiven;
   [self updateSectionWithCollapsibleItem:self.nonPersonalizedServicesItem
                                    items:self.nonPersonalizedItems
-                                 enabled:enabled];
+                  collapsibleItemEnabled:enabled
+                       switchItemEnabled:enabled
+                         textItemEnabled:enabled];
 }
 
-// Set a section (collapsible item, with all the items inside) to be enabled
-// or disabled.
+// Updates |collapsibleItem| and |items| using |collapsibleItemEnabled|,
+// |switchItemEnabled| and |textItemEnabled|.
 - (void)updateSectionWithCollapsibleItem:
             (SettingsCollapsibleItem*)collapsibleItem
                                    items:(ItemArray)items
-                                 enabled:(BOOL)enabled {
-  UIColor* textColor = enabled ? nil : [[MDCPalette greyPalette] tint500];
+                  collapsibleItemEnabled:(BOOL)collapsibleItemEnabled
+                       switchItemEnabled:(BOOL)switchItemEnabled
+                         textItemEnabled:(BOOL)textItemEnabled {
+  UIColor* textColor =
+      collapsibleItemEnabled ? nil : [[MDCPalette greyPalette] tint500];
   collapsibleItem.textColor = textColor;
   for (CollectionViewItem* item in items) {
     if ([item isKindOfClass:[SyncSwitchItem class]]) {
@@ -672,11 +679,11 @@ textItemWithItemType:(NSInteger)itemType
           NOTREACHED();
           break;
       }
-      switchItem.enabled = enabled;
+      switchItem.enabled = switchItemEnabled;
     } else if ([item isKindOfClass:[CollectionViewTextItem class]]) {
       CollectionViewTextItem* textItem =
           base::mac::ObjCCast<CollectionViewTextItem>(item);
-      textItem.enabled = enabled;
+      textItem.enabled = textItemEnabled;
     } else {
       NOTREACHED();
     }